1. Field of the Invention
The present invention relates to a robot control apparatus which comprises a servo amplifier having an AC/DC converter and used for driving a servo motor of a robot, which controls power that is supplied to the servo amplifier through a capacitor inrush current preventing resistor until the charging of a capacitor provided for the AC/DC converter in the servo amplifier is completed.
2. Description of the Related Art
In a prior art robot control apparatus, for example, a robot control apparatus disclosed in patent document 1 by the applicant of the present invention, the capacitor for the AC/DC converter in the servo amplifier is first charged through an inrush current preventing resistor, and after the charging of the capacitor is completed, power is supplied to the capacitor by bypassing the inrush current preventing resistor. Accordingly, to limit the driving of the robot, or more specifically, to limit the driving speed of the motor of the robot to a low speed, control has been performed by software in which a CPU executes a program, thereby sending a speed command to the servo amplifier via an axis controller.
[Patent Document 1] Japanese Patent Application No. 2006-129 (please refer to paragraphs [0002], [0003], and [0032] to [0046] in the specification and FIGS. 5 to 7 in the attached drawings]
In the prior art robot control apparatus, since power is supplied to the capacitor in the servo amplifier by bypassing the inrush current preventing resistor once the capacitor has been charged, it has not been possible to limit the driving of the robot by limiting the supply power through the inrush current preventing resistor.
Further, when teaching a robot a prescribed set of movements, an operator may desire to limit the driving speed of the robot, or more specifically, the speed of the servo motor of the robot, in order to ensure safety. Traditionally, this has been accomplished by software, in other words, by causing a CPU to execute a program and thereby sending a speed command to the servo amplifier via an axis controller. As a result, it has not been possible to limit the driving speed of the robot reliably, since the reliability of software is lower than that of hardware because of CPU runaway and bugs contained in the program.